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The all-star episode also featured a moving rendition of "Silent Night" in its cold open, a response to Friday’s school shooting in Connecticut.

Saturday Night Live’s cold open was pitch perfect for a nation mourning the deaths of 26 victims -- including 20 children -- in Friday’s Connecticut elementary school shooting. The NBC show put comedy aside and instead featured the New York City Children's Chorus singing “Silent Night.”

That was the only time the show addressed the tragedy, and the rest of the episode went on (as far as we know) as planned.

Minutes after the moving cold open, host Martin Short was onstage delivering a star-packed opening monologue. The comedian and former SNL castmember sang his PG-13 take on “The Most Wonderful Time of the Year,” with the idea that the holidays are all about being sexually forward.

“It’s the most amorous time of the year,” he sang. “All of those hotties about make your trousers stick out like a red nosed reindeer.”

Short went on to hit on a number of stars who showed up for the pre-Christmas episode, including Kristen Wiig, Jimmy Fallon and Tom Hanks. He tried to plant a kiss on Samuel L. Jackson but thought better of it and finally ran into Tina Fey and Lorne Michaels (who got an uncomfortably long kiss).

Paul McCartney performed three times, including a surprise reunion with surviving Nirvana members Dave Grohl, Krist Novoselic and Pat Smear. Hot off the supergroup’s performance at the 12-12-12 Hurricane Sandy relief concert, the band once again played “Cut Me Some Slack.”

But the most talked-about moment of the evening came when Jackson seemingly dropped an f-bomb during “What Up With That” --a BET sketch in which Kenan Thompson’s host is more interested in singing than letting the guests talk.

Jackson’s caricature of himself begins to speak about a charity he founded to help disadvantaged people during the holidays , when he’s cut off by yet another song.

“Don’t you dare cut me off!” Jackson screams and later says what sounds like “f—,” though Jackson later tweeted he only said one half of the word.

“I only said FUH not F--K! K was sposed to cut off da BULLSHIT, blew it!!” Jackson tweeted.

A sizable number of people online are saying they heard Jackson utter the full obscenity, and an unauthorized recording of the sketch uploaded to YouTube appears to confirm that. It's worth noting in the version posted on NBC.com, the word is muted.

"That costs money," Thompson said after the outburst, a reference to FCC fines.

One of the few sketches to play off the news saw an OB/GYN (Bill Hader) being briefed by Short in etiquette for delivering Kate Middleton’s baby. Playing off the real-life protocols that exist for greeting a royal, the doctor is told not to pull the baby from the birth canal unless the child first offers his or her hand. He’s also given a list of acceptable euphemisms for Middleton’s lady parts, including Thomas’ English muffin, Dame Judi Dench, the kingmaker and the Chunnel.

Like fellow rock legendMick Jagger back in May, McCartney closed the show with a sketch that morphed into a full-on performance. After playing Short’s much-abused musical partner (a poor sap relegated to playing the triangle), McCartney took the stage with “Wonderful Christmas Time.” The New York Children’s Chorus joined him for the song.

Other guest stars on the episode included Alec Baldwin, Paul Shaffer and Carrie Brownstein.

SNL is next new Jan. 19 with host Jennifer Lawrence and musical guest Lumineers.

So, what's your take on Jackson's possibly R-rated utterance? Sound off in the comments.